As Andy (akp982) suggests it would be wise to try a number of variation, other browsers on the same machine as the same user, another user on the same PC with both the preferred and other browsers and also have the user try to access her MOSS home page from an alternate, but similarly equipped PC.

You say you got her to clear her internet temp files, but there may also be value in clearing the browser history and cookies, restart the browser and have her try it again.